[linux-next20251118] BUG: Kernel NULL pointer dereference

[Venkat Rao Bagalkote]

Greetings!!


IBM CI has reported a boot crash while booting with linux-next2025118 
kernel.


Traces:


[    0.116026] audit: type=2000 audit(1763602256.110:1): 
state=initialized audit_enabled=0 res=1
[    0.116282] thermal_sys: Registered thermal governor 'fair_share'
[    0.116284] thermal_sys: Registered thermal governor 'step_wise'
[    0.120228] BUG: Kernel NULL pointer dereference at 0x00000000
[    0.120236] Faulting instruction address: 0xc0000000002b08a4
[    0.120241] Oops: Kernel access of bad area, sig: 11 [#3]
[    0.120245] LE PAGE_SIZE=64K MMU=Hash  SMP NR_CPUS=8192 NUMA pSeries
[    0.120252] Modules linked in:
[    0.120257] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G   D      
       6.18.0-rc6-next-20251118 #1 VOLUNTARY
[    0.120265] Tainted: [D]=DIE
[    0.120268] Hardware name: IBM,8375-42A POWER9 (architected) 0x4e0202 
0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
[    0.120273] NIP:  c0000000002b08a4 LR: c0000000002b04a4 CTR: 
0000000000000000
[    0.120278] REGS: c0000009fffffaa0 TRAP: 0380   Tainted: G D          
    (6.18.0-rc6-next-20251118)
[    0.120284] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 
48002828  XER: 20040006
[    0.120296] CFAR: c0000000002b04bc IRQMASK: 0
[    0.120296] GPR00: c0000000002b04a4 c0000009fffffd40 c000000001e58100 
0000000000000001
[    0.120296] GPR04: c000000002d68100 0000000000000007 0000000000000000 
0000000000000001
[    0.120296] GPR08: c000000005331e78 0000000000000400 c000000002d68100 
0000000000000000
[    0.120296] GPR12: 0000000000000000 c000000002f90000 0000000000000000 
c0000009fffffe94
[    0.120296] GPR16: 0000000000000000 c000000002cadb00 0000000000000000 
c000000003675e00
[    0.120296] GPR20: 0000000000000000 0000000000000000 0000000000000001 
00000000ffff8add
[    0.120296] GPR24: 0000000000000001 c00000000cacaa00 c000000002c72b00 
0000000000000000
[    0.120296] GPR28: c0000009fffffdb8 0000000000000000 c0000009e941b800 
c0000009e941b800
[    0.120353] NIP [c0000000002b08a4] sched_balance_rq+0x504/0x8b0
[    0.120361] LR [c0000000002b04a4] sched_balance_rq+0x104/0x8b0
[    0.120367] Call Trace:
[    0.120370] [c0000009fffffd40] [c0000000002b04a4] 
sched_balance_rq+0x104/0x8b0 (unreliable)
[    0.120379] [c0000009fffffe60] [c0000000002b1928] 
sched_balance_domains+0x298/0x3f0
[    0.120386] [c0000009ffffff00] [c00000000023d8d8] 
handle_softirqs+0x138/0x400
[    0.120394] [c0000009ffffffe0] [c000000000017da8] 
do_softirq_own_stack+0x38/0x50
[    0.120402] [c000000002c2fa20] [c00000000023cfe8] 
__irq_exit_rcu+0x198/0x1c0
[    0.120408] [c000000002c2fa50] [c00000000023e0ec] irq_exit+0x1c/0x40
[    0.120415] [c000000002c2fa70] [c00000000002a7e8] 
timer_interrupt+0x178/0x310
[    0.120421] [c000000002c2fad0] [c000000000009ffc] 
decrementer_common_virt+0x28c/0x290
[    0.120428] ---- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x2c
[    0.120435] NIP:  c0000000001ba998 LR: c0000000001c2584 CTR: 
0000000000000000
[    0.120440] REGS: c000000002c2fb00 TRAP: 0900   Tainted: G D          
    (6.18.0-rc6-next-20251118)
[    0.120445] MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 
22000222  XER: 20040006
[    0.120457] CFAR: 0000000000000000 IRQMASK: 0
[    0.120457] GPR00: 0000000000000000 c000000002c2fda0 c000000001e58100 
0000000000000000
[    0.120457] GPR04: 000000000000ffff 0000000000000000 0000000000000000 
0000000000000000
[    0.120457] GPR08: 0000000000000000 0000000000000000 80000000791afc00 
ffffffffffffffff
[    0.120457] GPR12: 0000000000000000 c000000002f90000 0000000000000000 
0000000000000000
[    0.120457] GPR16: 0000000000000000 0000000000000000 0000000000000000 
0000000000000000
[    0.120457] GPR20: 0000000000c00000 0000000000000008 0000000000000000 
0000000000000000
[    0.120457] GPR24: 0000000000000000 c000000000000000 c00000000a6e0000 
000000000bde2ca0
[    0.120457] GPR28: c000000002cad140 c0000000022418e0 c0000000022418e8 
c0000000022418e0
[    0.120513] NIP [c0000000001ba998] plpar_hcall_norets_notrace+0x18/0x2c
[    0.120519] LR [c0000000001c2584] pseries_lpar_idle.part.0+0x74/0x160
[    0.120524] ---- interrupt: 900
[    0.120527] [c000000002c2fda0] [c000000a0036d500] 0xc000000a0036d500 
(unreliable)
[    0.120534] [c000000002c2fe20] [c0000000000214ac] 
arch_cpu_idle+0x4c/0x110
[    0.120541] [c000000002c2fe40] [c0000000013a0ca0] 
default_idle_call+0x50/0x140
[    0.120547] [c000000002c2fe60] [c0000000002bb6ec] 
cpuidle_idle_call+0x1ac/0x240
[    0.120554] [c000000002c2feb0] [c0000000002bb878] do_idle+0xf8/0x1a0
[    0.120560] [c000000002c2fef0] [c0000000002bbba4] 
cpu_startup_entry+0x44/0x50
[    0.120566] [c000000002c2ff20] [c0000000000113ac] rest_init+0xec/0xf0
[    0.120572] [c000000002c2ff50] [c0000000020054c0] do_initcalls+0x0/0x18c
[    0.120580] [c000000002c2ffe0] [c00000000000ea9c] 
start_here_common+0x1c/0x20
[    0.120586] Code: eac1ffb0 eb21ffc8 eb41ffd0 eb81ffe0 ebc1fff0 
ebe1fff8 7c0803a6 4e800020 38c00000 3d4200f1 38e00001 3c8200f1 
<81260000> 394a1438 7d2807b4 7ca05028
[    0.120605] ---[ end trace 0000000000000000 ]---
[    0.120610]
[    1.113513] Kernel panic - not syncing: Fatal exception
[    1.122739] Rebooting in 10 seconds..



If you happen to fix this issue, please add below tag.


Reported-by: Venkat Rao Bagalkote <venkat88@xxxxxxxxxxxxx>


Regards,

Venkat.